Eddie Laux and Sergio Prado were at opposite ends of the fitness spectrum in high school. Laux was obese, and Prado was 120 pounds and six feet tall. Neither felt happy about their body -- until they got to college. Laux started rowing crew for Columbia and lost 70 pounds, and Prado joined Harvard's Karate Team and gained 60 pounds of muscle. Classic cases of caterpillars turning into butterflies…manly butterflies.

"We understood how much a body transformation can impact your life in so many different ways," Prado says. "We've learned this stuff, and we want to go on and help other people."

A year and a half ago, the duo released BodBot, an iOS, Android, and Windows Phone fitness app that acts like a personal trainer. Users enter in their personal information -- gender, workout gear, training goals, and preferred workout intensity. They then get a tailored set of daily exercises to perform.

The app's exercises change over time, increasing in intensity to help the user progress. The exercises also adjust based on whether someone completes their workout for the day, skips a set of reps, or adds in additional exercises. It's not a wearable, so the user has to program this information into the app. That said, the interface is easy enough to use and prompts you to do so.

Prado is an engineer -- formerly of Microsoft -- and Laux got his B.A. in neuroscience. Neither has a background in health, but Prado says that Laux studied fitness religiously when he first shed weight. They've used his expertise and research to design the different exercise programs. They spent two and a half years building the algorithm that would adjust based on an individual user's exercise patterns.

This is something that happens frequently in the appification of the world that makes me a little nervous. Non-experts -- people with tech backgrounds -- create tailored program for education or exercise or financial planning. People then use those apps, perhaps assuming that experts were consulted to design them, even if that's not the case.

I wrote about it recently with Palomar K-12, a free homeschooling portal where parents could get daily lessons for their children. But the lessons are aggregated off the Internet by a mom without a teaching background. The free offerings are helpful and attractive, but I was shocked that someone could homeschool their kids through a program that's detached from any regulation.

The same goes for BodBot -- health experts didn't create it, although the founders have run the app past personal trainers for a thumbs up. Essentially by following the plan you're relying on the wisdom of two guys in their mid 20s. That said, I suppose when you sign up for a personal trainer session at 24 Hour Fitness and you get some steroid, neck vein-y muscle monster, that's not much better.

Whatever my reservations are, BodBot has done well enough to support its bootstrapped founders. Laux and Prado haven't raised venture funding, using their savings to build and launch the app, along with the proceeds of a successful crowd funding campaign to the tune of $61,000. They're now profitable, having just passed a quarter of a million users. The app itself is free, but there's a premium version you can pay for to track your vitals more carefully.

The difference between BodBot and a FitBit or Up band is that it's looking forward from the quantifiable self. It's not just about tracking your movements, calories intake, or exercises. BodBot focuses on the future: this is what you did today, so what should you do tomorrow? It's a natural evolution.

Speaking of the future, BodBot may be an app today, but Prado hopes it will be a wearable tomorrow. "We haven't looked at wearables as extensively as one would, but wearables are becoming the sort of thing that smart phones are now, where people are buying up patents," Prado says. "That's definitely a very real substantive challenge we'll have to deal with moving into that space."

Now they just need to make an app that helps people be happy with the skin they're in.